It is known to print surface coverings, such as sheet goods and tiles, with two or more print layers. The surface coverings are made by printing the print layers on one or more elongated sheets. If the surface covering is a plurality of tiles, the elongated sheet is cut to form a plurality of tiles.
With the rotogravure printing process, each color is printed with a separate print cylinder. To obtain sharpness and clarity in the printed pattern, the print cylinders are made with the same repeat length and the successive print cylinders are aligned so that the printed patterns precisely aligned to yield a sharp image.
The print cylinders that are presently used in the industry have lengths of about 40″ and circumferences of about 24″ or 36″. Therefore, if the printed pattern of the surface covering is an image of tiles measuring approximately 12″×12″, the print cylinders produce a maximum of 6 or 9 different 12″×12″ printed patterns that may be cut to form 6 or 9 tiles having different printed patterns.
The tiles are typically put in cartons directly from the cutting line. Therefore, 2 or 3 different tiles are packed into each carton and the customer is told to mix the tiles from different cartons. Even if the tiles are mixed prior to packing in the cartons, each carton can contain a maximum of 6 or 9 differently patterned tile. Depending on the thickness of the tiles and the size of the tiles (12″×12″, 16″×16″ or 18″×18″, for example), a carton may contain 14, 30 or 45 tiles, for example.
When a floor is laid with the tiles, it is fairly easy to find the repeat patterns by locating a distinctive image relative to the edges of one tile and finding the same distinctive image relative to the edges on another tile. It would be advantageous to avoid this pattern repeat.
If the surface covering is a sheet good, the repeat length of the pattern is determined by the circumference of the print cylinder or about 24″ or 36″. Again, it is fairly easy to find the repeating pattern in a floor laid with the sheet good.
Tile measuring 16″×16″ are made with print cylinders having 32″ or 48″ circumferences. Again, since the cylinders are no more than 40″ in length, 4 or 6 different tile patterns are produced and the repeat length of sheet goods with a 16″×16″ tile pattern would be 32″ or 48″.